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Male genitalia
The human male reproductive system is a series of organs located outside of the body and around the pelvic region of a male that contribute towards the reproductive process. The male contributes to reproduction by producing spermatozoa. The spermatozoa then fertilize the egg in the female body and the fertilized egg (zygote) gradually develops into a fetus, which is later born as a child. Testes The testes hang outside the abdominal cavity of the male within the scrotum. They begin their development in the abdominal cavity but descend into the scrotal sacs during the last 2 months of fetal development. This is required for the production of sperm because internal body temperatures are too high to produce viable sperm. Penis The penis has a long shaft and enlarged tip called the glans penis. The penis is the copulatory organ of the males. When the male is sexually aroused, the penis becomes erect and ready for intercourse. Erection is achieved because blood sinuses within the erectile tissue of the penis become filled with blood. The arteries of the penis are dilated while the veins are passively compressed so that blood flows into the erectile cartilage under pressure. The male penis is made of two different tissues, soft spongey tissue and cartilage. There is a pelvic bone in the front top of the penis. Sperm & seminal fluid A mature spermatoza, or spermatozoon, has 3 distinct parts: a head, a mid-piece, and a tail. The tail is made up of microtubules that form cilia and flagella, and the mid-piece contains energy-producing mitochondria. The head contains 23 chromosomes within a nucleus. The tip of the nucleus is covered by a cap called the acrosome, which is believed to contain enzymes needed to breach the egg for fertilization. A normal human male usually produces several hundred million sperm per day. Sperm are continually produced throughout a male's reproductive life, though production decreases with age. During ejaculation, sperm leaves the penis in a fluid called seminal fluid. This fluid is produced by 3 types of glands, the seminal vesicles, the prostate gland, and Cowper's glands (bulbourethral glands). Each component of a seminal fluid has a particular function. Sperm are more viable in a basic solution, so seminal fluid has a slightly basic pH. Seminal fluid also acts as an energy source for the sperm, and contains chemicals that cause the uterus to contract.There is a tiny gland that holds sperm. Internal genital organs Epididymis The epididymis is a whitish mass of tightly coiled tubes cupped against the testicles. It acts as a maturation and storage place for sperm before they pass into the vas deferens, tubes that carry sperm to the ampullary gland and prostatic ducts. Vas deferens The vas deferens also known as the sperm duct is a thin tube approximately 17 inches long that starts from the epididymis to the pelvic cavity. Testes The testes, also known as the testicles, are the anatomically male gonads, the organs that produce sperm cells. The testes are egg-shaped structures that grow to be about one inch long and rest inside the scrotum. The testes also produces hormones, including testosterone, which stimulates the production of sperm cells and facilitates male maturation. Accessory glands Three accessory glands provide fluids that lubricate the duct system and nourish the sperm cells. They are the seminal vesicles, the prostate gland, and the bulbourethral glands (Cowper glands). Seminal vesicles Seminal vesicles are sac-like structures attached to the vas deferens at one side of the bladder. They produce a sticky, yellowish fluid that contains fructose. This fluid provides sperm cells energy and aids in their motility. Prostate gland The prostate gland surrounds the ejaculatory ducts at the base of the urethra, just below the bladder. The prostate gland is responsible for the production of semen, a liquid mixture of sperm cells, prostate fluid and seminal fluid. Bulbourethral glands The bulbourethral glands, also called Cowper glands, are two small glands located on the sides of the urethra just below the prostate gland. These glands produce a clear, slippery fluid that empties directly into the urethra. It produces substances related to nourishment of spermatozoa. See also * Artificial insemination * Circumcision * Female reproductive system * Secondary sex characteristic * Sexual development External links Category:Male reproductive system Category:Urogenital system